1. Field of the Invention
The present invention relates to a system and method for purifying or desalinating water while conserving natural resources, such as fossil fuels, minerals, and land, and making use of renewable energy sources, such as solar, wind, and tidal power. More particularly, the present invention relates to a system and method having an Archimedean screw to elevate water from a brine source and a vertical series of filters for desalinating the water as gravity moves the water through the filters. Renewable energy sources are used to power the Archimedean screw and a turbine is used to recapture some of the energy from the descending water to power the screw. The system occupies a small surface area to conserve land and recovers brine salts and minerals from the desalination.
2. Prior Art
The necessity of water for sustaining life, combined with the limited supply of usable water, make water a valuable resource or commodity in numerous parts of the world. Many areas of the world have been repeatedly plagued with droughts leading to famine and disease. The lack of water, or use of poor quality water, causes or transmits diseases such as malaria, cholera, diarrhea, typhoid, hepatitis, dysentery, etc. Even in prosperous agricultural areas, water rights and shares cause contentions, strife, and litigation.
Despite its essential nature, fresh water appears to be a declining resource. Two factors contributing to the decreasing water supply include population growth and global warming. As the population grows, less water is available per person from existing water sources. Global warming refers to the probability that the earth is subject to hotter temperatures, due at least in part to the growing use of fossil fuels which produce global warming gases. Climatologists have asserted that the consequences of higher temperatures will include hotter summers, irregular weather patterns, reservoir evaporation and agricultural stress. Another factor contributing to the lack of fresh water includes industrial pollution of water systems. Therefore, increased population, global warming/climate changes, and pollution are combining to reduce the amount of water available per person.
Many solutions have been proposed to remedy the dwindling water supply. Such solutions include water conservation programs and devices, and the construction of new reservoirs, pipelines, etc. These proposals have several disadvantageous. For example, conservation techniques and water storage are both limited by current water resources. With a growing population and limited water supply, the shortage gap will continue to increase. Water conservation will undoubtedly remain an important factor; however, there is a limit to the amount of existing fresh water that can be stored and conserved. Furthermore, dams, pipelines and other structural solutions damage the environment and displace wildlife.
Another well known solution to the decreasing water supply is desalination of salt water. Desalination involves the removal of salt, or brine, from salt water to produce potable, or drinkable, water. Desalination is attractive due to its potential to convert the largest source of water, the ocean, into usable water. Desalination appears particularly promising for many cities with coastal locations. Despite its promise and potential, however, desalination has failed to emerge as a prevailing solution or source of fresh water. Perhaps the biggest factor discouraging expansion of desalination utilities is the high cost associated with the process.
There are many desalination methods for removing salt from salt water. Current desalination methods include distillation, crystallization, electro dialysis, and reverse osmosis. The disadvantages of these methods and systems are that they are either not sufficiently developed and/or are too expensive. For example, large amounts of energy are consumed in most desalinization process, making the commercialization cost prohibitive compared to other fresh water sources. Furthermore, many of these systems require large areas of land, which is usually unavailable in coastal areas with large populations. In fact, land costs have been specifically identified as one of the largest costs of desalinization.
Other desalination proposals include microbial, solar, hydrogen, and even nuclear fusion. Microbial desalting refers to eliminating sodium in seawater similar to a bacterium altering sodium ions during respiration. Solar desalting refers to the use of either solar panels or solar cells to desalt water. Hydrogen desalting refers to the process of using the hydrogen in water as a power source to desalt water. Nuclear fusion desalting refers to a potentially benign process which uses the latent power of the atom.
Despite the above existing and proposed methods for desalination, a cost effective solution has not yet emerged. Therefore, it would be advantageous to develop a system and method to produce potable water from a brine or other water is source. In addition, it would be advantageous to develop such a system and method to produce potable water while conserving energy. In addition, it would be advantageous to develop such a system and method to produce potable water while conserving natural resources, such as fossil fuels, land, minerals, water, etc. In addition, it would be advantageous to develop such a system and method to produce potable water that makes use of renewable energy sources, such as solar, wind, and tidal power. In addition, it would be advantageous to develop a system and method for desalinating water and recovering the brine for other uses.